import java.util.HashSet;


class NumJewelsInStones {
    public int numJewelsInStones(String jewels, String stones) {
        HashSet<Character> set = new HashSet<>();
        for (int i = 0;i < jewels.length();i++) {
            set.add(jewels.charAt(i));
        }
        int count = 0;
        for (int j = 0; j < stones.length(); j++) {
            if (set.contains(stones.charAt(j))) {
                count++;
            }
        }
        return count;
    }
}
